Control means and system of control



Oct. 16, 1956 c. SCHINDLER 2,767,369

CONTROL MEANS AND SYSTEM OF CONTROL Filed April l, 1951? 2 sheets-sheet1 JNVENTOR. f2 2 car; weal-mozzar- Oct. 16, 1956 e. SCHINDLER 2,767,369

CONTROL MEANS AND SYSTEM OF CONTROL Filed April 1,. 1953 2 Sheets-Sheet2 INVENTOR. Car'Z 62h irzdZer United States Patent Cari Schindler,Wauwatosa, Wis., Electric Company, Milwaukee, Delaware Application April1, 1953, Serial No. 346,065 13 Claims. (Cl. 32343.5)

assignor to McGraw Wis., a corporation of This invention relates tocontrol means and to a system of control and is particularly directedtoa system of voltage control, though it is to be understood that in itsbroader aspect this invention can be followed in the control ofdifferent quantities.

It is an object of the present invention to provide a system of controlresponsive to voltage fluctuations, and which includes a hydraulicallyoperated servo mechanism, which is self-compensating to permit theactuating mechanism to float at normal or neutral position with aminimum amount of hunting.

It is another object of this invention to provide a control means andsystem of control for use in voltage regulation, and which is readilyadaptable for use in actuating as current, reactive volt amperes', orpower.

Specifically, it is an object of the present invention to provide anelectrical servo mechanism which does not frictionally actuated sliplever.

Further objects and advantages of the present inventhe control means.

Fig. 3 is a sectional view of another embodiment of the working cylindermember of the control means.

Referring to Fig. l, a transformer has been indicated generally by thereference character 1. It is provided with a primary 2 and a secondary 3connected, respectively, to the power line 4 and the load line 5. A tapchanger indicated generally by the reference character 6 is provided onthe primary side of the transformer. This tap changer 6 is preferably ofthe multiple point, snap action type very commonly and widely used.

A voltage sensitive device in the form of an electromagnetic solenoidcoil is electrically connected across the load or secondary line 5, andis generally denoted by the reference character 7. It will be apparentfrom the hereinafter description that the sensitive device may take anyof various forms, such as current transformers, DArsonval instruments,and the like (not shown), which may be made responsive to current,reactive volt amperes, or power. As presently described, the devicetakes the form of a voltage coil 8 arranged to receive a magneticplunger or armature 9, fastened at its upper end to a zero adjustat itslower end to a pivot pin 11.

The armature 9 may be made of a temperature sensitive magnetic alloy,commonly used for devices of this nature where ambient temperaturesmight alfect the delicate response of the voltage sensitive device.Temperature compensator alloys are generaly of iron-nickel alloys andave their magnetic permeability proportional to change in temperature.

The pivot pin 11 is attached to the operating end 12 of an actuatingmember or cantilever 13 which is rotatably response to voltagefluctuation at a maximum sensitivity, the cantilever 13 is preferablymounted on ball or roller bearings 15 on the shaft 14.

The outer end 16 of the cantilever is arranged to receive one end ofcompensating springs 17 and 18, which are fastened at their oppositeends to a compensating lever 19 rotatably supported on the supportingshaft 14, and 20 and 2-1. This may be clearly compensating lever 19 isbiased 1n an axial direction relative to the shaft 14 by means of acompression spring 23 engaging a slidable friction plate 24, which abutsthe lever 19, forcing it towards frictional engagement with a crank 25.The crank 25 is also rotatably mounted on the shaft 14 and is providedwith a. flange 26 which acts as a stop for the spring 23. The crank ispivotally connected to a link 27 which, in turn, is pivotally attachedto a yoke 28 having opposed pistons 29 received by of the workingcylinder bores are each closed at one end and communicate only through aslide valve, which is denoted generally by the reference character 35.

The slide valve includes outlet ports 36 and 37 comits ends. portion 41is open and close the inlet port 42, communicating with a pump 43arranged to supply oil or other hydraulic fluid under pressure. Theslide member 40 is operatively asoperating end 12 of the cantilevermember 13 by means of a pivoted link member 44.

It is to be understood that the entire mechanism may be immersed in oil,if so desired, and that the same oil maybe used as the hydraulic media.When so immersed, the unit will not have the tendency to becomeairbound. The pump is shown here diagrammatically, but it is to beunderstood that it may take any of various forms, and if tion or theoperation of the control means. The slide valve 35 communicates withworking cylinder member 34 through the ports 45 and, 46, respectively.28 is connected at its upper end to a con-tact actuator, which may takethe form of a U-shaped trunnion 47 supporting a pivot pin 48, which isrotatably connected to an actuating linkage 49. The actuating linkage 49is operatively connected to the snap action tap changer 6, so that todrop downwardly with respect to the solenoid, as shown in Fig. 1'. Itwill be" noted that the plunger 9 is resiliently supported at its top bymeans of a zero adjustment screw 10. This downward movement of theplunger will cause the cantilever 13 to rock in a counterclockwisedirection about the shaft 14, and will simultaneously cause the linkmember 44 to move downwardly. The counterclockwise movement of thecantilever will draw the compensating spring 18 in tension against anequalizing compressive action on the compensating spring 17. Thecompensating lever 19 will, accordingly, be biased towardscounterclockwise motion about the shaft 14.

The simultaneous downward motion of the link member 44 will actuate theslide member 40 of the slide valve 35 towards a downward direction, asviewed in Fig. l. The downward motion of the slide member 4% will openthe outlet port 37 by the sliding action of the gate member 39 and alsoopen the inlet port 42 by the sliding action of the integral gateportion 41. It will be noted that there is a free passageway above thelower piston 31 through the port 46 and out the inlet port 37,permitting unimpeded movement of the lower piston 30 in eitherdirection.

The hydraulic fluid, which is under pressure transmitted by the pump 43,will be forced through the port 45 into the bore 32 of the workingcylinder member 34. This pressure will be imparted to the upper piston29, causing a simultaneous upward movement of the yoke 28 and theactuating linkage 49 through the trunnion 47. It will be apparent thatsuch upward motion will cause the tap changer 6 to raise the voltage onthe load line or secondary line responsive to the position of thecontacts connected to the primary 2 of the transformer 1.

Referring again to the upward motion of the yoke 28, this movement,which occurs simultaneously with the change of taps, will be imparted tothe link 27 pivotally attached to the crank 25. The upward motion of thelink 27 will tend to cause the crank 25 to rotate about the shaft 14 ina clockwise direction. Attention is drawn to the fact that the crankfrictionally engages the compensating lever 19, which lever has beenpreviously biased towards a counterclockwise direction about the shaft14 by means of the action of the compensator springs 17 and 18responsive to the motion of the outer end 16 of the cantilever 13. Thecompensating lever 19 is prevented from excess rotational movement bymeans of the stops 20 and 21 engageable therewith.

The immediate effect of the compensating mechanism is to reduceovertravcl of the piston 29 to cause the tap changer to move beyond thedesired degree of regulation. Obviously, this will reduce wear and tearon the regulator and switch taps in addition to reducing unnecessaryvoltage fluctuation and flickering of electric lamps on the regulatedcircuit. The compensating device also permits the mechanism to floatbetween taps as long as the normal voltage exists. The compensatinglever 19 is nothing more than a slip lever frictionally contacting thecrank 25, permitting the floating action no matter which tap might beengaged by the tap changer switch blade. The frictionally driven leverand the compensating spring connection will tend to slip past the crankafter a period of time has expired when the tap change has beencompleted, to permit the mechanism to float at the new position andsupply normal secondary voltage. It will be apparent that the positionsof compensation may be determined by the size and force exerted by thecompensating springs 17 and 18.

When normal secondary voltage has been restored, th s voltage will beimmediately reflected in the voltage sensitive device 7, causing thezero adjusted plunger 9 to seek its normal operating position. Thenormal operating position will be immediately reflected in the slidemember 40 to close the inlet port 42 and the outlet ports 36 and 37.This ac 'on will permit an equihbrium condition to exist between thepistons 29 and 30 responsive to the compensation provided by means ofthe lever 19 and the crank 25.

It will be apparent that the device will operate in substantially thesame manner as above described when an overvoltage condition exists. Theexistence of an overvoltage will be reflected in the voltage sensitivedevice 7 to cause the plunger 9 to move in an upward direction with aconsequent opening of the inlet port 42 to permit the pressurizedhydraulic fluid to enter the port 46 to the bore 33 of the workingcylinder member 34, which will force the piston 30 in a downwarddirection and concurrently operating'the tap changer to move to a lowervoltage tap position. The port 45 will permit any trapped fluid toescape out through the opened outlet port 36 for unimpeded motion of theupper piston 29. The same compensating effect will take place betweenthe lever 19 in the crank 25, but in an opposite direction about theshaft 14 than as described in connection with undervoltage conditions inthe load or secondary 5. The device will then float at the new tap witha minimum of hunting between taps as compensated for between the members19 and 25.

The preferred embodiment of the control means has been described inconnection with a dual-chamber cylinder supplying pressure to twoindependently operable piston members each joined to a linking yoke.However, the device may conveniently take the form illustrated by Fig. 3without departing from the scope of invention.

Like parts relating to both embodiments bear the same referencecharacter in each of the figures of the drawings. The embodiment of Fig.3 is illustrative of a single piston 50 having dual working faces, andwhich is axially slidable in the bore 51 of the working cylinder member52. The working cylinder member is closed at both ends except for anopening in each end sealed by means of gaskets 53 and 54, respectively.The gaskets 53 and 54 are arranged to receive piston rods 55 and 56,respectively. The rods 55 and 56 extend from either face of the pistonmember 50 and are joined at their outer ends to pivot trunnions 47 and57, respectively. Ports 45 and 46 provide an entrance and an exit meansfor the pressurized hydraulic fluid, which is alternatively admitted andexpelled in substantially the same manner as described in connectionwith the preferred embodiment. The compensating means, which hashereinabove been fully described, is adapted to operate in the samemanner with the present embodiment through the link 27 and the pistonrods 55 and 56 integrally positioned on the piston 50.

It will be apparent that a novel form of an electrical quantityregulation control means and system has been provided by this invention,which includes a compensating means immediately responsive to quantityvariations, simultaneous to the reaction of an acutator member, whichsubstantially eliminates objectionable hunting common to many regulatingservo mechanisms.

I claim:

1. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including dual pressure chambers each having apiston slidable therein, condition responsive means responsive tovariations in said electrical quantity and including a solenoid coil andmagnetic plunger, said plunger comprising a temperature sensitivemagnetic alloy having its magnetic permeability proportional to changein ambient temperature, a selective slide valve jointly associated withsaid working cylinder and with a source of hydraulic fluid underpressure to alternatively admit said fluid to said dual chambers, acantilever actuator jointly operatively associated with said plunger andwith said valve, said actuator being rotatively positioned on a shaftmember and having a portion extending radially from said shaft member, acrank rotatable on said shaft member and operatively associated withsaid piston members, and a compensating member rotatable relative tosaid shaft member and frictionally engaged radially relative to saidcrank, opposed spring members each conjointly engaging said compensatingmember and the radially extending portion of said actuator, wherebymovement of said magnetic plunger will simultaneously actuate said slidevalve and said compensating member through the medium of said actuatorand said opposed spring members to permit balanced movement of saidpistons in a preselected direction alternatively responsive tovariations in said electrical quantity.

2. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including a piston arranged for actuation ofsaid control means, condition responsive means responsive to variationsin said electrical quantity, a selective slide valve jointly associatedwith said Working cylinder and with a source of hydraulic fluid underpressure to selectively admit said fluid to said cylinder, an actuatorjointly operatively associated with said condition responsive means andwith said valve, and compensating means for providing balanced movementof said piston and comprising a pair of frictionally engaged relativelymovable members, one of said movable members being connected to saidpiston, and force balancing means interconnecting the other of saidrelatively movable members and said actuator, whereby movement of saidcondition responsive means will simultaneously actuate said slide valveand said other of said relatively movable members through the medium ofsaid actuator and said force balancing means to permit balanced movementof said piston in a preselected direction alternatively responsive tovariations in said electrical quantity.

3. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including a piston arranged for actuation ofsaid control means, condition responsive means responsive to variationsin said electrical quantity, a selective slide valve jointly associatedwith said working cylinder and with a source of hydraulic fluid underpressure to se lectively admit said fluid to said cylinder, an actuatorjointly operatively associated with said condition responsive means andwith said valve, and compensating means for providing balanced movementof said piston and comprising a shaft member, a crank rotatable uponsaid shaft member and operatively connected to said piston, acompensating member positioned on and rotatable relative to said shaftmember, said compensating member and said crank being frictionallyengaged radially relative to one another, and force balancing meansinterconnecting said compensating member and said actuator, wherebymovement of said condition responsive means will simultaneously actuatesaid slide valve and said compensating member through the medium of saidactuator and said force balancing means to permit balanced movement ofsaid piston in a preselected direction alternatively responsive tovariations in said electrical quantity.

4. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including a piston arranged for actuation ofsaid control means, condition responsive means responsive to variationsin said electrical quantity, selective valve means jointly associatedwith said working cylinder and with a source of hydraulic fluid underpressure to selectively admit said fluid to said cylinder, an actuatorjointly operatively associated with said condition responsive means andwith said valve means, and compensating means for providing balancedmovement of said piston and comprising a shaft member, a crank rotatableupon said shaft member and operatively connected to said piston, acompensating member positioned on and rotatable relative to said shaftmember, said compensating member and said crank being frictionallyengaged radially relative to one another, and force balancing meansinterconnecting said compensating member and said actuator, wherebymovement of said condition responsive means will simultaneously actuatesaid valve means and said compensating member through the medium of saidactuator and said force balancing means to permit balanced movement ofsaid piston in a preselected direction alternatively responsive tovariations in said electrical quantity.

5. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including a piston arranged for actuation ofsaid control means, condition responsive means responsive to variationsin said electrical quantity, a selective slide valve jointly associatedwith said working cylinder and with a source of hydraulic fluid underpressure to selectively admit said fluid to said cylinder, an actuatorjointly operatively associated with said condition responsive means andwith said valve, and compensating means for providing balanced movementof said piston and comprising a shaft member, a crank rotatable uponsaid shaft member and operatively connected to said piston, acompensating member positioned on and rotatable relative to said shaftmember, said compensating member and said crank being frictionallyengaged radially relative to one another, and balanced resilient meansinterconnecting said compensating member and said actuator, wherebymovement of said condition responsive means will simultaneously actuatesaid slide valve and said compensating member through the medium of saidactuator and said balanced resilient means to permit balanced movementof said piston in a preselected direction alternatively responsive tovariations in said electrical quantity.

6. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including dual pressure chambers, each havinga piston slidable therein and each piston arranged for alternativeactuation of said control means, condition responsive means responsiveto variations in said electrical quantity, a selective slide valvejointly associated with said Working cylinder and with a source ofhydraulic fluid under pressure to alternatively admit said fluid to saiddual chambers, a cantilever actuator jointly operatively associated withsaid condition responsive means and with said valve, said actuator beingrotatively positioned on a shaft member and having a portion extendingradially from said shaft member, a crank rotatable on said shaft memberand operatively associated with said piston members, and a compensatingmember rotatable relative to said shaft member and frictionally engagedradially relative to said crank, balanced resilient means conjointlyengaging said compensating member and the radially extending portion ofsaid actuator, whereby movement of said condition responsive means willsimultaneously actuate said slide valve and said compensating memberthrough the medium of said actuator and said resilient means to permitbalanced movement of said pistons in a preselected directionalternatively responsive to variations in said electrical quantity.

7. In an alternating current electrical system having adjustable controlmeans to control the magnitude of an electrical quantity of said system;a hydraulic work cylinder including dual pressure chambers, each havinga piston slidable therein and each piston arranged for alternativeactuation of said control means, condition responsive means responsiveto variations in said electrical quantity and including a solenoid coiland magnetic plunger, a selective slide valve jointly associated withsaid Working cylinder and with a source of hydraulic fluid underpressure to alternatively admit said fluid to said dual chambers,acantilever actuator jointly operatively associated with said plungerand with said valve, said actuator being rotatively positioned on ashaft member and having a portion extending radially from said shaftmember, a crank rotatable on said shaft member and operativelyassociated with said piston members, and a compensating member rotatablerelative to said shaft member and frictionally engaged radially relativeto said crank, opposed spring members each conjointly engaging saidcompensating member and the radially extending portion of said actuator,whereby movement of said magnetic plunger will simultaneously actuatesaid slide valve and said compensating member through the medium of saidactuator and said opposed spring members to permit balanced movement ofsaid pistons in a preselected direction alternatively responsive tovariations in said electrical quantity.

8. In a pressure fluid operated controlling device including a hydraulicwork cylinder having a piston for actuating a member to be controlled,condition responsive means, a selective slide valve jointly associatedwith said working cylinder and with a source of hydraulic fluid underpressure to selectively admit said fluid to said cylinder, thecombination therewith of an actuator jointly operatively associated withsaid condition responsive means and with said valve, and compensatingmeans for providing balanced movement of said piston and comprising apair of frictionally engaged relatively movable members, one of saidmovable members being connected to said piston, and force balancingmeans interconnecting the other of said relatively movable members andsaid actuator, whereby movement of said condition responsive means willsimultaneously actuate said slide valve and said other of saidrelatively movable members through the medium of said actuator and saidforce balancing means to permit balanced movement of said piston in apreselected direction alternatively responsive to conditions affectingsaid condition responsive means.

9. In a pressure fluid operated controlling device including a hydraulicwork cylinder having a piston for actuating a member to be controlled,condition respon sive means, a selective slide valve jointly associatedwith said working cylinder and with a source of hydraulic fluid underpressure to selectively admit said fluid to said cylinder, thecombination therewith of an actuator jointly operatively associated withsaid condition responsive means and with said valve, and compensatingmeans for providing balanced movement of said piston and comprising ashaft member, a crank rotatable upon said shaft member and operativelyconnected to said piston, a compensating member positioned on androtatable relative to said shaft member, said compensating member andsaid crank being frictionally engaged radially relative to one another,and force balancing means interconnecting said compensating member andsaid actuator, whereby movement of said condition responsive means willsimultaneously actuate said slide valve and said compensating memberthrough the medium of said actuator and said' force balancing means topermit balanced movement of said piston in a preselected directionalternatively responsive to conditions aifecting said conditionresponsive means. l

10. In a pressure fluid operated controlling device including ahydraulic work cylinder having a piston for actuating a member to becontrolled, condition responsive means, selective valve means jointlyassociated with said working cylinder and with a source of hydraulicfluid under pressure to selectively admit said fluid to said cylinder,the combination therewith of an actuator jointly operatively associatedwith said condition responsive means and with said valve means, andcompensating means for providing balanced movement of saidpiston andcomprising a shaft member, a crank rotatable upon said shaft member andoperatively connected vto said piston, a compensating member positionedon and rotatable relative to said shaft member, said compensating memberand said crank being frictioually engaged radially relativeto oneanother, and force balancing means interconnecting said compensatingmember and said actuator, whereby movement of said condition responsivemeans will simultaneously actuate said valve means and said compensatingmember through the medium of said actuator and said force balancingmeans to permit balanced movement of said piston in a preselecteddirection alternatively responsive to conditions affecting saidcondition responsive means.

11. In a pressure fluid operated controlling device including ahydraulic work cylinder having a piston for actuating a member to becontrolled, condition responsive means, a selective slide valve jointlyassociated with said working cylinder and with a source of hydraulicfluid under pressure to selectively admit said fluid to said cylinder,the combination therewith of an actuator jointly operatively associatedwith said condition responsive means and with said valve, andcompensating means for providing balanced movement of said piston andcomprising a shaft member, a crank rotatable upon said shaft member andoperatively connected to said piston, a compensating member beingfrictionally engaged radially relative to one another, and balancedresilient means interconnecting said compensating member and saidactuator, whereby movement of said condition responsive means willsimultaneously actuate said slide valve and said other of saidcompensating member through the medium of said actuator and saidbalanced resilient means to permit balanced movement of said piston in apreselected direction alternatively responsive to conditions aflectingsaid condition responsive means.

12. In a pressure fluid operated controlling device including ahydraulic work cylinder having dual pressure chambers, each having apiston slidable therein and each piston arranged for alternativelyactuating a member to be controlled, condition responsive means, aselective slide valve jointly associated with said working cylinder andwith a source of hydraulic fluid under pressure to alternatively admitsaid fluid to said dual chambers, the combination therewith of acantilever actuator jointly operatively associated with said conditionresponsive means and with said valve, said actuator being rotativelypositioned on a shaft member and having a portion extending radiallyfrom said shaft member, a crank rotatable on said shaft member andoperatively associated with said piston members, and a compensatingmember rotatable relative to said shaft member and frictionally engagedradially relative to said crank, balanced resilient means conjointlyengaging said compensating member and the radially extending portion ofsaid actuator, whereby movement of said condition responsive means willsimultaneously actuate said slide valve and said compensating memberthrough the medium of said actuator and said balanced resilient means topermit balanced movement of said pistons in a preselected directionalternatively responsive to conditions aifecting said conditionresponsive means.

13. In a pressure fluid operated controlling device including ahydraulic work cylinder having dual pressure chambers, each having apiston slidable therein and each piston arranged for alternativelyactuating a member to be controlled, condition responsive meansincluding a solenoid coil and magnetic plunger, a selective slide valvejointly associated with said working cylinder and with a.

source of hydraulic fluid under pressure to alternatively admit saidfluid to said dual chambers, the combination therewith of a cantileveractuator jointly operatively associated with said plunger and with saidvalve, said actuator being rotatively positioned on a shaft member and.

having a portion extending radially from said shaft memher, a crankrotatable on said shaft member and operatively associated with saidpiston members, and a compensating member rotatable relative to saidshaft member and frictionally engaged radially relative to said crank,opposed spring members each conjointly engaging said compensating memberand the radially extending portion of said actuator, whereby movement ofsaid plunger will simultaneously actuate said slide valve and saidcompensating member through the medium of said actuator and said opposedspring members to permit balanced movement of said pistons in apreselected direction alternatively responsive to conditions affectingsaid condition responsive means.

References Cited in the file of this patent UNITED STATES PATENTS875,463 Schmitthenner Dec. 31, 1907 0 Ziebolz Tiebel Polson et al.Lawrence Muzzey Meredith Beman Weinfurt Schultz FOREIGN PATENTS FranceDec. 31, 1940 June 8, 1954 July 11, 1949

